This invention relates generally to systems and methods for treating liquids carrying suspended or dissolved solids and more particularly to separating the solids from the liquid in order to recover reusable liquids such as potable water and/or dry solids.
Throughout the world there exists an ever-increasing number of operating facilities faced with brine or wastewater disposal problems. These aqueous solution disposal problems span a wide range of industries including oil & gas production, food processing, ethanol production and inland brackish water desalination. Suspended solids can be readily removed using conventional separation technologies. However, the removal of dissolved solids and contaminants in solution often requires numerous unit processes and can lead to ponding or storage of these liquid wastes while awaiting a cost-effective disposal solution. The negative impact of these problems grows significantly when the ponding approach leads to the contamination of a groundwater and/or surface water resource.
Several methods are known for treating wastewaters and other brines, as well as for the desalination of seawater and brackish waters. Notable techniques include mechanical vapor recompression (MVR) evaporator systems that have been widely accepted and applied within numerous inland power plants to achieve zero liquid discharge (ZLD), particularly in water-short regions of the U.S. These systems are believed to be capable of concentrating brine to a maximum of 200,000 ppm (20%) total dissolved solids (TDS), prior to any subsequent processing in pursuit of ZLD.
Most conventional evaporator systems have a significant potential for fouling or scaling of the heat transfer surfaces resulting from the precipitation of solids as the concentration level is increased. The addition of scale control chemicals to eliminate scaling constituents within the seawater fed to seawater desalination evaporator systems is common practice. Of particular concern within any brine concentrator system are the inverse solubility constituents, including calcium carbonate (CaCO3), calcium sulfate (CaSO4), and magnesium hydroxide (MgOH), that will begin to precipitate on the heat transfer surfaces at temperatures above 120 F. The fouling or scaling of heat transfer surfaces continues to be a major area of concern within the field of seawater desalination wherein the brine concentration rarely, if ever, exceeds about 100,000 ppm or 10% TDS.
Accordingly, there is a need for a cost-effective solution to the problems encountered in treating saltwater, wastewater and/or non-aqueous solutions to recover reusable water (or other liquid) and/or dry solids.